A designer rate regime is one that allows CFCs effectively to choose the amount of tax they pay such that the local tax amount is 75% or above the amount of the corresponding UK tax. This enables CFCs to meet the condition at step 3 of TIOPA10/S371NB and qualify for the tax exemption. Designer rate regimes are listed in Regulations - see S.I. 2000/3158(web). If the CFC has a designer rate of tax, then the tax exemption cannot apply.